Method of electroslag remelting and device effecting

ABSTRACT

A method of electroslag remelting of consumable electrodes in which the agents improving the quality of the ingot are blown into the melt so that the injected flows of these agents cause rotation of this melt. A mold for electroslag remelting of consumable electrodes in the process of simultaneously blowing agents to the melt which improve the quality of the ingot, in which the mold is provided with at least one nozzle for blowing said agents into said melt, and in which case the longitudinal axis of said nozzle is inclined to the walls of the mold under an angle other than a right angle. A consumable electrode provided with a nozzle for blowing agents into the melt to improve the quality of the ingot, which nozzle is in the form of a coil wound on the electrode and made of the material being melted.

j '22 Filed:

United States atent [1 Paton et a1.

1.11] 3,852,510 1 Dec. 3, 1974 1 1 METHOD OF ELECTROSLAGREMELTING AND DEVICE EFFECTING [76] Inventors: Boris Evgenievich Paton, ulitsa Kotsjubinskova, 5, kv. 21; Boris Izhailevich Thedovar, bulvar Lesi Ukrainki, 2, kv. 6; Jury Vadimovich Latash, Vozdukhoflotsky prospekt, 81, kv. l4; Leonty Vasilievich Chekotilo, ulitsa Scharbakova, 49a, 7

kv. 10; July Georgievich Emelyanenko, ulitsa Darvina, 5, kv. 5; Vasily lvandvich Us, ulitsa Saxaganskogo, 58, kv. l2; Vitaly Mikhailovich Baglai, ulitsa Semashko, 10, kv. 54/3; Viktor Mikhailovich Martyn, ulitsa Vernadskogo, 65, kv. 102; Viktor Leonidovich Artamonov, ulitsa Sovskaya, 9, kv. 4; Oleg Petrovich Bondarenko, ulitsa Kreschatik, l5, kv. 34; Georgy Alexandrovich Boiko, ulitsa V1, Libedskaya, l6, kv. 106; Anatoly Konstantinovich Isikulenko, ulitsa Babushkina, 23, kv. 38; Vasily Vladimirovich lvon, Darnitskoe shosse, 107/2, kv. l0; Leonid Viktorovichlavlov, Borschagouskaya ulitsa, 234, kv. .6,

' all of Kiev, U,.S.S.R.

Dec. 17, 1973 Appl. No.: 425,550

Related US. Application Data [60] Continuation of set. No. 339,068, March 8, 1973,,

abandoned. Division of Ser. No. 125.744, March 18, 1971, Pat. No. 3,767,294.

52 vs. C]. 13/18 51 int. Cl. nosb 7/06 58 Field of Search 13/9, 9 ES, 18

[56] 5 References Cited UNlTED STATES PATENTS 3,318,686 5/1967 Schulte 13/33 UX 3,472.649 10/1969 I Slbakin ct a1. 13/33 UX Primary ExaminerR. N. Envall, Jr. Attorney, Agent, or Firml-lolman & Stern 5 7] ABSTRACT A method of electroslag remelting of consumable electrodes in which the agents improving the quality of the ingot are blown into the melt so that the injected flows of these agents cause rotation of this melt. A mold for electro slag remelting of consumable electrodes in the process of simultaneously blowing agents to the melt which improve the quality of the ingot, in which the mold is provided with at least one nozzle for blowing said agents into said melt, and in which case the longitudinal axis of saidnozzle' is inclined to the walls of the mold under an angle other than a right angle. A consumable electrode provided with a nozzle for blowing agents into the melt to improve the quality of the ingot, which nozzle is in the form of a coil wound on the electrode and made of the material being melted.

2 Claims, 13 Drawing Figures PATENTELBEB 31915 3.852510 sum 6 or BACKGROUND OF THE INVENTION The present invention relates to electrometallurgy and, more particularly, to a method of electroslag remelting of consumable electrodes and to devices for effecting this method. More specifically, the invention relates to the production of ingots of high-quality electroslag metal.

PRIOR ART Well known in the art is a method of electroslag remelting of consumable electrodes in molds, in which a controllable gas atmosphere is created above the electroslag bath. Inthis case, saturation of the remelted metal with deleterious gases from the surrounding atmosphere is eliminated but required degasification of the metal is not achieved. 1

In addition, when large ingots are produced by the method of electroslag remelting of high-dimension consumable electrodes with a higher content of gases H N and deleterious impurities (S, P, etc.), it is necessary not only to prevent the saturation of the re- I melted metal with gases from the surrounding atmosphere, but also to intensify the process of degasification, to increase the purity of the metal by excluding deleterious impurities and non-metallic inclusions, as well as to improve the formation of the ingots of the electroslag remelting which can not be provided by means of the known method.

In present-day metallurgy, there is also well known a method of gas treatment of molten metal consisting in blowing (bubbling) of the metal by gases and powders in a gas flow, thus somewhat improving the melt quality. During the bubbling, the mixing of the melt takes place only near the injected flow, while dead zones are formed in separate portions of themelt, in which the'process of 'degasification and cleaning it from the deleterious and non-metallic inclusions (Pb, Sn, etc.) is

not adequately intensive, and this deteriorates the quality of the obtained ingots.

OBJECTS AND SUMMARY OF THE INVENTION The principal object of the invention is to provide an improved method of electroslag remelting of consumable electrodes by which there is ensured an intensive stirring (rotation) of the melt within the mold throughout the whole volume of this melt in the process of remelting.

Another object of the invention is to provide a device for effecting the proposed method.

These and other objects are attained due to the fact that in the proposed method of electroslag remelting of consumable electrodes, the agents contributing to an improvement-of the quality of the ingot are. injected into the melt in such a manner that they cause rotation of this melt. It is expedient that'the agents injected into the slag and metal portions of the melt are blown in opposite directions.

To equalize the speeds of rotation of the slag and metal portions of the melt, the agents are preferably sponding number of the portions separately and in opposite directions in the adjacent portions. The agents are preferably blown into the slag portion of the melt directly under the consumable electrodes.

The above objects are also attained due to the fact that the mold for carrying out the method is provided with a nozzle for injecting the agents into the melt in the form of a coil of a metal being remelted wound inside the mold along the walls thereof.

The mold is preferably provided with at least one additional nozzle in the form of a coil of a melted material, the melting point, of which differs from the melting point of the material of the main coil, with the additional nozzle being located respectively to the main coil and having a winding directed in opposition to the winding of the main coil.

In the mold at least at one level within the slag portion of the melt, there can be located, at least one nozzle for the injection of the agents intothe melt, the nozzle being in the form of a branch pipe mounted into the lateral wall of the mold, with the longitudinal axis ofthe branch pipe being directed tangentially to the mold wall.

It is expedient to mount several groups of pipe branches in the mold walls for injection of the agents into the melt with various angles of inclination of their axes to the walls of the mold to provide for several zones of rotation of the melt within the mold with different directions of rotation in the adjacent zones, the number of the zones corresponding to that of the groups of pipe branches.

In the mold having a widened upper portion, the nozzles for blowing the agents into the slag portion are preferably arranged in the bottom of the upper widened portion of the mold directly under the consumable electrodes.

The bottom of the upper widened portion of the mold is preferably provided with removable inserts into which there are mounted said pipe branches for blowing the agents into the slag portion of the melt.

The nozzles for blowing the agents into the melt are preferably provided with porous inserts of refractory metals.

The mold can be made sectional along a vertical line and have at least two sections, in which case the mold walls in the place of jointing the sections should be provided with a hermetically sealed chamber communicating through a slot with the bath of melt and through a vchannel with the source of agent improving the quality of the metal being melted.

The consumable electrode is preferably provided with at least one additional nozzle shaped as a coil BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a device for electroslag remelting with a mold provided with a nozzle in the form of a coil, according to the invention, the view being partly in section and partly in elevation;

FIG. 2 is a sectional view taken along the line II-II in FIG. I, the view looking in the direction of the arrows;

FIG. 3 is a view in section showing a device for electroslag remelting with a mold according to the invention provided with nozzles in the form of pipe branches mounted into the wall of the mold;

FIG. 4 is a sectional view along the line IV-IV in FIG. 3, the view looking in the directionof the arrows;

' portion according to the invention;

FIG. 8 is a view insection showing a device for electroslag remelting with a sectional mold, according to the, invention;

no. 9 is a sectional view taken along the line rx--rx in'FlG. 8,'the view looking in the direction of the arrows;

FIG. 10 is a view in section showing a device for electo be melted and is designed for blowing into a slag portion 5 and into a metal portion 6 of the melt, agents assisting inimproving the quality of the ingots, for example gases (Ar, He, N CO etc.), a mixture of various gases (.Ar 0 etc. gas-powder mixtures (Ar CaF etc.), aerosols,- et cetera In addition, the device is provided with a current supply source 7, one terminal of which is connected to a consumable electrode 8 constituted by a massive rod and the other terminal of which is connected to the pan 2. v

In the embodiment of the invention shown in FIG. ii, a single coil, 4 is used. Other modifications of the device may be equipped with a plurality of coils. In this case, the winding of the additional coils should be directed opposite to the winding of the main coil. The additional coils are also made of the material to be melted but their melting point should differ from the melting point of the main coil.

In FIG. 2 there is illustrated the position of the'coil 4 and consumable'electrode 8 relative to the walls of the mold I and also the disposition and shape of the cross section of the consumable electrode 8. I I

' FIG. 3 shows a device for electroslag remelting which differs from the modification shown in-FIGS. l and 2 in that it is provided with nozzles for injection of the agent in the form of pipe branches 9 mounted into the side walls of the mold 1. Depending on the cross section of the mold l, the number of pipe branches 9 may be varied. The pipe branches. 9 are disposed both within the zone of the slag portion 5 and the zone of metal the portion 6 of the melt. In the device shown in FIGS. 3 and 4, four pipe branches 9 are located along the diameter of the mold l at one'level within the zone troslag remelting with a consumable electrode, according to the invention, the consumable electrode being provided with a nozzle in the form of a coil; I

FIG. III is a view section showing adevice for electroslag remelting with a mold intended for simultaneously melting several separate ingots;

. FIG. 12 is a sectional view taken along the line XII- of the slag portion 5 and four pipe branches 9 are located at one level within the zone of metal portion 6 of the melt. I

In addition, in FIG. 4 it can be seen that the pipe I branches 9 are mounted tangentially to the walls of the mold l and are located in such a manner that the flows of agents blown through these pipe branches cause rotation of the slag portion 5 and the metal portion 6 of the melt'in opposite directions I FIG. 5 illustrates a modification of the device for electroslag remelting used for producing ingots of a large cross section. In this case, unlike the, abovedescribed modifications of the remelting device, the mold l is provided with nozzles for injection of the agent which are in the form of pipe branches 11 mounted in the walls of the mold l atseveral levels 10 along the height of the mold l. The distance between the levels 10 is selected so that during the whole pro- -XII in FIG. 11, the view looking in the direction of the arrows and FIG. 13 is a fragmentary view partly in elevation and partly in section of an embodiment in which at least a second coil is wound on the rod, with the winding thereof being in a direction opposite to the winding of the first coil.

- DETAILED DESCRIPTION OF THE EMBODIIVENTS The device for electroslag remelting (FIG. 1 consists of a water-cooled mold l, a pan 2, pipe branches 3 for the supply and removal of the cooling agents and a nozzle in the form of a coil 4 wound within the mold l along the walls thereof. The coil 4 is made of a material 1 cess of melting, both the slag portion 5 and the metal portion 6 of the melt are blown with theagents.

The pipe branches 1 1, depending on the cross section of the mold, are combined into several groups 12 (FIG. 6) in each of which the longitudinal artes of the pipe branches 11 are inclined at such angles to the wall of the mold 1 that in the process of injection of the agents into the melt through these pipe branches, formed within the melt are-several zones 13 of rotation corresponding to the number of groupslZ with an opposite direction of rotation'within the 6 showsfour such zones 13.

FIG. 7 shows a versionof the device for electroslag remelting with'a mold having a widened upperportion l4 and a group of consumable electrodes 15 located I along the periphery of the ,upperportion 14. In this adjacent zones 13. FIG.

case, the nozzles for feeding the agent into the melt in the form of pipe branches 16 are preferably located in a bottom 17 of the widened upper portion 14 of the mold directly under the consumable electrodes 15. The pipe branches 16 are mounted in replaceableinserts 18 which are mounted in the bottom 17. The supply of the agent to the pipe branches from the source (not shown in FIG. 7) of agent is effected from a distributing unit 19 through channels 20.

The disposition of the pipe branches 16 for blowing the agents into the slag portion 5 of the melt directly under the consumable electrode allows the agent to be used not only for treatment of molten metal 21 but also drops 22 and thin film 23 of molten metal formed on the meltable ends of the consumable electrodes 15.

To use the agent for treatment of the metal portion 6 of the melt, the lower portion of the mold 1 is preferably made in the form of a collector (not shown in FIG. 7) into the walls of which there are mounted nozzles for feeding the agents through the gapbetween the ingot and the internal wall of the collector into the melt, with the above-said nozzles being in the form of pipe branches.

FIG. 8 illustrates is a version of the device for electroslag remelting provided with a sectional mold. In this case, the nozzles for supplying-the agent into the slag portion 5 and metal portion 6 of the melt consist of slots 24 formed in the places of connection of sections 25 by the planes 26 thereof. The planes 26 have a knurling 27 (FIG. 9). In this construction, the agent is supplied to the slots 24 from the'source (not shown) in FIGS. 8 and 9, through channels 28 and through herm'etically sealed chambers 29 in the walls of the mold FIG. 10 is a version of the device for electroslag remelting by means of a consumable electrode 8 provided with a nozzle for blowing an agent into the slag portion 5 of the melt, with the nozzle being of the material being melted and shaped as a coil 311 which, unlike the version shown in FIGS. 1 and 2 is wound around the consumable electrode 8.

FIGS. 11 and 12 shows a modification of the device for electroslag remelting provided with a mold l de-' signed for melting several ingots simultaneously.

In this embodiment, unlike the.abovedescribed devices, the mold 1 is provided with a bottom 31 having a central portion 32 protruding into the mold l, with said central portion 32 having a cup 33 serving as a collector of the metal portion 6 of the melt and openings 34 (FIG. 12) used for shaping the ingot being melted and located along the periphery of the bottom 31. The nozzles for blowing the agent into the melt are in the form. of pipe branches 35 mounted in the walls of the central portion 32 of the bottom 31 at levels corresponding to the position of the slag portion 5 and metal portion 6 of the melt.

In FIG. 13 is disclosed an embodiment in which at least one additional nozzle 30a in the form of a second coil is wound on the rod 8, with the winding of the additional or second coil being in a direction opposite to the winding of the first coil 30. The additional coil is of a material havinga melting point differing from the melting point of the first coil.

The device for electroslag remelting shown in FIGS. 1 and 2 operates, according to the invention, in the following manner Prior to the process of electroslag remelting, the mold 1 provided with a nozzle of the material being melted in the form of a coil 4 is placed onto the pan 2. A starting rod 36 is also placed on the pan 2, and thereafter the consumable electrode 8 .is inserted into the mold ll. After that then, an electric current from the current source 7 is applied to the consumable electrode 8 and the pan 2. From the source of agent, (not shown in FIGS. 1 and 2) the agent is fed into the coil 4, while the cooling medium is fed into-the jacket of the mold 1 and the pan 2. Then, molten slag is poured into the mold l to form a slag portion of the melt (bath) until a current appears in the circuit, the consumable electrode 8, the pan 2, which current causes melting of the electrode 8.

During the whole process of melting, the consumable electrode 8 is fed into the mold 1 at a rate equal to the rate of melting thereof. As fast as the consumable electrode melts, molten metal is collected in the mold l forming a metal portion 6 of the melt, with said metal gradually solidifying into an ingot 37. In the process of melting, the ingot 37 is builtup, and the metal portion 6 and the slag portion 5 ascend within the mold 1. In this case, simultaneously with the melting of the consumable electrode 8, there is effected the melting of the coil 4, wound inside the mold 1 along the walls thereof, at a rate equal to the speed of rising of the slag and metal portions 5 and 6'of the melt. The agent forced from the end of the coil 4, which is withinthe slag portion 5 of the melt during the whole process of melting,

bubbles the slag portion 5 and partially the metal portion 6 of the melt and simultaneously rotates them about the vertical axis of the mold l.

This makes it possible to considerably intensify the process of degasification and refining of the metal of the ingot 37. I

The device for electroslag remelting shown in FIGS. 3 and 4 operates similarly to the device shown in FIGS. 1 and 2 with the single distinction that the ingot 37in the process of melting is withdrawn from the mold I at a speed which enables the slag and metal portions 5 and 6 of the melt during the whole process of melting to be in the mold 1 at the same level of the agent-injecting nozzles shaped as pipe branches I s In addition, as the longitudinal axes of the pipe branches 9 located within the zone of slag portion '5 of the melt are directed opposite tothe longitudinal axes of the longitudinal axes of the pipe branches 9 located within the zone of the metal portion 6 of the melt and are tangentially mounted into the walls of the mold 1, the agent blownthrough these pipe branches cause" rotation of the slag and metalportions 5 and 6, respectively, in opposite directions.

The electroslag remelting device shown in FIGS. 5 and 6 operates similarly to the device shown in FIGS. 1 and 2, with the difference being that the agent is blown through the nozzles shaped as pipe branches 11 mounted into the walls of the mold 1 and combined into four independent groups 12.

The agent blown through the pipe branches l1 simultaneously bubbles and rotates the slag and metal porcauses opposite rotation of the melt in the adjacent zones 13.

The device for electroslag remelting shown in FIG. 7 and designed for remelting of a-group of consumable electrodes 15 operates similarly to the device shown in FIGS. 3 and 4. However, in this case during the whole' process of melting, the agent is blown through the pipe branches 16 located in the bottom 17 of the widened 1 portionl4 of the mold into the slag portion 5 of the melt directly under the consumable electrodes 15. The flows of the agent injected into the melt and encountering the drops 22 and the thin film 23 of molten metal on the melted ends of the consumable electrodes erode them and treat the metal (degasification and refining).

Furthermore, due to the fact that the bottom 17 of the widened upper portion 14 of the mold is cooled, a porous slag skin 38 is formed on the bottom 17 in-the places of disposition of the pipe branches 16 after pouring the slag into the mold. The agentblown through the pipe branches 16 intov the slag portion 5 of the melt, while passing through the slag skin 38, is pulverized into fine fractions and bubbles the slag and metal portions 5 and 6 of the melt, as well as the drops 22 and the film 23 of molten metal, by small blisters 39. This provides fora better treatment of the melt by the agent,

thereby improving the quality of the ingot 37. i

The electroslagremelting device shown in FIGSQS and 9 operates similarly to the device shown in FIGS. 3 and 4, with the only differe'ncebeing that the agent injected into the slag and metal portions 5 and 6 of the melt is blown by small blisters along the entire perimeter of the mold through the nozzles in the form of slots 24communicating with a source of agent (not'shown in FIGS. 8 and 9) through a hermetically sealed chamber 29 and channels 28.

The electroslag remelting device shown in FIG. 10 operates similarly to the device shown in FIGS. 1 and 2, but in this case, the agent is injected'intothe slag portion 5 of the melt through a nozzle made of thematerial being melted and shaped as a coil 30 wound on the consumable electrode 8. During the melting, the consumable electrode 8 and the coil 30 are continuously fed into the mold l in which they are melted tot r- The electroslag remelting device shown in FIGS. 11 and 12 operates similarly to'the device shown in FIGS. 3and 4, with the only difference consisting in that the agent is blown into the slag portion! and the metal portion 6 of the melt through nozzles in the formof pipe branches mounted in the walls of the central portion 32 of the bottom 31.

The agent blown through the pipe branches 35 simultaneously bubbles and rotates the metal portion 6' of the melt not only in the openings 34 shaping the ingot 37 but also in the cup 33 of the central portion'32 of the bottom 31. This provides for a more complete treatment of the whole metal portion of the melt, thus improving the quality of theingot 37 being melted.

In the above-described modifications of the device, the pipe branches for blowing the agent into the melt are provided. with porous inserts 40 (shown in the modification of the device in FIGS. 3 and 4) made of refractory materials (for example porous W, Mo, etc.). This makes it possible to inject the agent into the melt by fine streams or mist and this increases the quality of treatment of the melt by the agent.

The advantages of the present invention consist in that during the electroslag remelting of consumable electrodes according to the proposed method, the bubbling of the melt by an agent improving the quality of the ingot is associated with the rotation of the melt throughout the whole volume of the mould and this makes it possible to considerably intensifythe process of degasification of themelt and cleaning of the same from deleterious impurities, non-metal inclusions and fusible impurities as well as improve the surface of the ingot which eventually increase the quality of the ingot being melted. 1 I v v i The rotation of the slag portion andmetal portion of the melt in opposite directions increases the path of the agent through the metal portion of the melt and assists melted.

' ond coil being in a'direction'oppositeto the winding of The proposed method can be effected by means of devicesbuilt around known electroslag remelting apparatus having a simple construction and featured by a low cost of manufacture and this is still another advantage of the proposed invention. I

We claim: v I I 1. A consumable electrode for use with a. mold for effecting electroslag remelting,,comprising amassive rod, and a nozzlefor blowing agents into the ,melt in the mold forv improving the quality of the ingot, the nozzle being a coil wound aroundsaidrod and made of. the same material as the-rod.

comprising at least one additional nozzle in the form of a second coil wound on said red, the windin g ofjthe secthefirst named coil, the additional nozzle being of a material having a melting point differing fromlthe melting point of the first named coiLy f 2. The consumableelectrode as-claimledin claim I 

1. A CONSUMABLE ELECTRODE FOR USE WITH A MOLD FOR EFFECTING ELECTROSLAG REMELTING, COMPRISING A MASSIVE ROD AND A NOZZLE FOR BLOWING AGENTS INTO THE MELT IN THE MOLD FOR IMPROVING THE QUALITY OF THE INGOT THE NOZZLE BEING A COIL WOUND AROUND SAID ROD AND MADE OF THE SAME MATERIAL AS THE ROD.
 2. The consumable electrode as claimed in claim 1, comprising at least one additional nozzle in the form of a second coil wound on said rod, the winding of the second coil being in a direction opposite to the winding of the first named coil, the additional nozzle being of a material having a melting point differing from the melting point of the first named coil. 